Method of forming an oral care implement

ABSTRACT

An oral care implement having a handle, and a head having a main body that is coupled to the handle. The head may include a release component coupled to the main body. The release component may include a water-dissolvable matrix comprising a first polymer having a processing temperature greater than or equal to 150° C. The oral care implement may include a plurality of tooth cleaning elements. A method of forming an oral care implement which includes injection molding a composition comprising a graft polymer onto a head of an oral care implement at a temperature equal to or greater than 130° C. to form a water-dissolvable polymer matrix.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.16/200,745, filed on Nov. 27, 2018, which claims the benefit of U.S.Provisional Application No. 62/590,827, filed on Nov. 27, 2017. Thedisclosure of the above applications are incorporated herein byreference.

BACKGROUND

Toothbrushes comprising water-soluble release polymers are known toprovide a release of a desired component to the user. The effect of suchwater-soluble release polymers was to provide a perceivable response bythe user—such as color change—after the water-soluble polymer wasexposed to water during usage. However, previously, such water-solublerelease polymers have rapid release profiles—releasing the desiredcomponent within days of the first usage, thereby making those polymersunsuitable to last the entire lifespan of the oral care implement.Alternatively, such water-soluble release polymers may require lowprocessing temperatures (less than 130° C.) because such polymersundergo severe degradation at temperatures above 130° C., therebydestroying the controlled release characteristics. Having such lowprocessing temperatures creates long manufacturing times.

Thus, there exists a need for an oral care implement comprising awater-soluble release composition that can be formed at hightemperatures without undermining the desired release characteristics.

BRIEF SUMMARY

The present invention is directed to an oral care implement comprising ahandle; and a head having a main body that is coupled to the handle, thehead comprising: a release component coupled to the main body, therelease component comprising a water-dissolvable matrix comprising afirst polymer having a processing temperature greater than or equal to150° C.; and a plurality of tooth cleaning elements.

According to other embodiments, the present invention includes an oralcare implement comprising a handle; and a head having a main bodycoupled to the handle, the head comprising a release componentcomprising a water-dissolvable matrix comprising a graft polymer havingunits formed from caprolactam, vinyl acetate, and ethylene glycol; and aplurality of tooth cleaning elements.

Other embodiments of the present invention include a method of formingan oral care implement comprising injection molding a compositioncomprising a graft polymer onto a head of an oral care implement at atemperature equal to or greater than about 150° C. to form awater-dissolvable polymer matrix.

Other embodiments of the present invention include a method of formingan oral care implement comprising injection molding a compositioncomprising a graft polymer onto a head of an oral care implement at atemperature equal to or greater than about 150° C. to form awater-dissolvable polymer matrix.

In other embodiments, the present invention is directed to a method offorming an oral care implement comprising injection molding acomposition comprising a blend of a graft polymer and an additive onto ahead of an oral care implement at a temperature equal to or greater than130° C. to form a water-dissolvable polymer matrix; wherein the additivehas a decomposition temperature less than or equal to 150° C.

In other embodiments, the present invention includes a method of formingan oral care implement comprising injection molding a compositioncomprising a blend of a graft polymer and an additive onto a head of anoral care implement at a temperature equal to or greater than 110° C. toform a water-dissolvable polymer matrix, wherein the additive has avapor pressure of at least about 0.18 atm at 100° C.

In other embodiments, the present invention is directed to an oral careimplement comprising: a handle; and a head having a main body that iscoupled to the handle, the head comprising: a front surface and a rearsurface, a plurality of open cavities are formed into the rear surfaceof the head, a release component coupled to the main body positioned inat least one of the plurality of open-ended cavities; and a plurality oftooth cleaning elements; wherein the release component comprises awater-dissolvable matrix comprising a first polymer having a processingtemperature greater than or equal to 130° C.

Other embodiments of the present invention include a method of formingan oral care implement comprising: injection molding a composition at atemperature equal to or greater than 130° C. to form a water dissolvablebody, the composition comprising a water-dissolvable graft polymer thatforms a matrix in the water dissolvable body; positioning the waterdissolvable body on a head of an oral care implement.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is front perspective view of an oral care implement in accordancewith an embodiment of the present invention;

FIG. 2 is a rear perspective view of the oral care implement of FIG. 1;

FIG. 3 is a close-up view of area III of FIG. 2;

FIG. 4 is a close-up view of area III of FIG. 2 before injection moldinga release composition;

FIG. 5 is a rear view of the head of the oral care implement of FIG. 1;

FIG. 6 is a side view of the head of the oral care implement of FIG. 1;and

FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6.

DETAILED DESCRIPTION

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

As used throughout, ranges are used as shorthand for describing each andevery value that is within the range. Any value within the range can beselected as the terminus of the range. In addition, all references citedherein are hereby incorporated by referenced in their entireties. In theevent of a conflict in a definition in the present disclosure and thatof a cited reference, the present disclosure controls.

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. The amounts given are based on the active weightof the material.

The description of illustrative embodiments according to principles ofthe present invention is intended to be read in connection with theaccompanying drawings, which are to be considered part of the entirewritten description. In the description of embodiments of the inventiondisclosed herein, any reference to direction or orientation is merelyintended for convenience of description and is not intended in any wayto limit the scope of the present invention. Relative terms such as“lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,”“down,” “top,” and “bottom” as well as derivatives thereof (e.g.,“horizontally,” “downwardly,” “upwardly,” etc.) should be construed torefer to the orientation as then described or as shown in the drawingunder discussion. These relative terms are for convenience ofdescription only and do not require that the apparatus be constructed oroperated in a particular orientation unless explicitly indicated assuch.

Terms such as “attached,” “affixed,” “connected,” “coupled,”“interconnected,” and similar refer to a relationship wherein structuresare secured or attached to one another either directly or indirectlythrough intervening structures, as well as both movable or rigidattachments or relationships, unless expressly described otherwise.Moreover, the features and benefits of the invention are illustrated byreference to the exemplified embodiments. Accordingly, the inventionexpressly should not be limited to such exemplary embodimentsillustrating some possible non-limiting combination of features that mayexist alone or in other combinations of features; the scope of theinvention being defined by the claims appended hereto.

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. The amounts given are based on the active weightof the material. According to the present application, the term “about”means+/−5% of the reference value. According to the present application,the term “substantially free” less than about 0.1 wt. % based on thetotal of the referenced value.

Referring first to FIGS. 1 and 2 concurrently, an oral care implement100 is illustrated in accordance with one embodiment of the presentinvention. In the exemplified embodiment, the oral care implement 100 isin the form of a manual toothbrush. However, in certain otherembodiments the oral care implement 100 can take on other forms such asbeing a powered toothbrush, a tongue scraper, a gum and soft tissuecleanser, a water pick, an interdental device, a tooth polisher, aspecially designed ansate implement having tooth engaging elements, orany other type of implement that is commonly used for oral care. Thus,it is to be understood that the inventive concepts discussed herein canbe applied to any type of oral care implement unless a specific type oforal care implement is specified in the claims.

The oral care implement 100, which generally comprises a head 110 and ahandle 120, extends from a proximal end 101 to a distal end 102 along alongitudinal axis A-A. The head 110 extends from a proximal end 118 to adistal end 119 along a longitudinal axis that is coextensive with thelongitudinal axis A-A of the oral care implement 100. Furthermore, inthe exemplified embodiment the distal end 102 of the oral care implement100 is the same as the distal end 119 of the head 110.

The handle 120 is an elongated structure that provides the mechanism bywhich the user can hold and manipulate the oral care implement 100during use. In the exemplified embodiment, the handle 120 is genericallydepicted having various contours for user comfort. Of course, theinvention is not to be limited by the specific shape illustrated for thehandle 120 in all embodiments and in certain other embodiments thehandle 120 can take on a wide variety of shapes, contours, andconfigurations, none of which are limiting of the present inventionunless so specified in the claims. The handle 120 may include a neckportion 122 that extends to the proximal end 118 of the head 110.

In the exemplified embodiment, the handle 120 is formed of a hard orrigid plastic material, such as for example without limitation polymersand copolymers of ethylene, propylene, butadiene, vinyl compounds, andpolyesters such as polyethylene terephthalate. The handle 120 alsoincludes a grip 121 that is formed of a resilient/elastomeric material.In the exemplified embodiment, the grip 121 is molded over a portion ofthe handle 120 that is typically gripped by a user's thumb andforefinger during use. Furthermore, it should be appreciated thatadditional regions of the handle 120 can be overmolded with theresilient/elastomeric material to enhance the gripability of the handle120 during use. For example, portions of the handle 120 that aretypically gripped by a user's palm during use may be overmolded with athermoplastic elastomer or other resilient material to further increasecomfort to a user. Furthermore, materials other than those noted abovecan be used to form the handle 120, including metal, wood, or any otherdesired material that has sufficient structural rigidity to permit auser to grip the handle 120 and manipulate the oral care implement 100during tooth brushing.

The head 110 of the oral care implement 100 is coupled to the handle 120and comprises a front surface 111 and an opposing rear surface 112.Furthermore, the head 110 comprises a peripheral surface 113 extendingbetween the rear surface 112 and the front surface 111. In theexemplified embodiment, the head 110 is formed integrally with thehandle 120 as a single unitary structure using a molding, milling,machining, or other suitable process. However, in other embodiments thehandle 120 and the head 110 may be formed as separate components whichare operably connected at a later stage of the manufacturing process byany suitable technique known in the art, including without limitationthermal or ultrasonic welding, a tight-fit assembly, a coupling sleeve,threaded engagement, adhesion, or fasteners. Thus, the head 110 may, incertain embodiments, be formed of any of the rigid plastic materialsdescribed above as being used for forming the handle 120, although theinvention is not to be so limited in all embodiments and other materialsthat are commonly used during toothbrush head manufacture may also beused.

As discussed further herein, the oral care implement 100 also comprisesa release component 150 extending from the rear surface 112 of the head110. The oral care implement 100 also comprises a plurality of toothcleaning elements 115 extending from the front surface 111 of the head110. The invention is not to be limited by the structure, pattern,orientation, and material of the tooth cleaning elements 115 in allembodiments. Furthermore, where it does not conflict with the otherdisclosure provided herein or the claims, it should be appreciated thatthe term “tooth cleaning elements” may be used in a generic sense torefer to any structure that can be used to clean, polish, or wipe theteeth and/or soft oral tissue (e.g. tongue, cheek, gums, etc.) throughrelative surface contact. Common examples of “tooth cleaning elements”include, without limitation, bristle tufts, filament bristles, fiberbristles, nylon bristles, polybutylene terephthalate (PBT) bristles,spiral bristles, rubber bristles, elastomeric protrusions, flexiblepolymer protrusions, combinations thereof, and/or structures containingsuch materials or combinations. Thus, any combination of these toothcleaning elements may be used within the tooth cleaning elements 115 insome embodiments. Furthermore, where bristles are used for one or moreof the tooth cleaning elements 115, such bristles can be tapered,end-rounded, spiral, or the like.

In embodiments that use elastomeric materials to form one or more of thetooth cleaning elements 115, suitable elastomeric materials may includeany biocompatible resilient material suitable for uses in an oralhygiene apparatus. To provide optimum comfort as well as cleaningbenefits, the elastomeric material of any such tooth cleaning elementmay have a hardness property in the range of A10 to A70 Shore hardnessin one embodiment, or A8 to A25 Shore hardness in another embodiment.One suitable elastomeric material is styrene-ethylene/butylene-styreneblock copolymer (SEBS) manufactured by GLS Corporation.

Nevertheless, SEBS material from other manufacturers or other materialswithin and outside the noted hardness range could be used.

The tooth cleaning elements 115 may be coupled to the head 110 in anymanner known in the art, including staples, in-mold tufting (IMT),anchor-free tufting (AFT), or a modified AFT known as AMR. Referringbriefly to FIGS. 4 and 7, one manner in which the tooth cleaningelements 115 are secured to the head 110 via AFT will be described.Specifically, in the embodiment exemplified the tooth cleaning elements115 are formed as a cleaning element assembly on a head plate 130 suchthat one or more of the tooth cleaning elements 115 are mounted onto thehead plate 130 and then the head plate 130 is coupled to the head 110.In such an embodiment, the head plate 130 is a separate and distinctcomponent from the head 110 of the oral care implement 100. However, thehead plate 130 is connected to the head 110 at a later stage of themanufacturing process by any suitable technique known in the art,including without limitation thermal or ultrasonic welding, any fusiontechniques such as thermal fusion, melting, a tight-fit assembly, acoupling sleeve, threaded engagement, adhesion, or fasteners. Thus, thehead plate 130 and the head 110 are separately formed components thatare secured together during manufacture of the oral care implement 100.

In certain embodiments, the head plate 130 may comprise an upper surface133 and a lower surface 132. The upper surface 133 of the head plate 130forms a portion of the front surface 111 of the head 110 when the headplate 130 is coupled to the head 110 as discussed herein. The head plate130 comprises a plurality of holes 131 formed therethrough from theupper surface 133 to the lower surface 132, and the tooth cleaningelements 115 may be mounted to the head plate 130 within the holes 131.Specifically, in AFT a plate or membrane (i.e., the head plate 130) iscreated separately from the head 110. The tooth cleaning elements 115(such as bristles, elastomeric elements, and combinations thereof) arepositioned into the head plate 130 so as to extend through the holes 131of the head plate 130. The free ends 117 of the tooth cleaning elements115 on one side of the head plate 130 perform the cleaning function. Theanchor portions 116 of the tooth cleaning elements 115 on the other sideof the head plate 130 are melted together by heat to be anchored inplace. As the tooth cleaning elements 115 are melted together, a meltmatte 106 is formed. The melt matte 106 is a thin layer of plastic thatis formed by melting the anchor portions 116 of the bristles so that theanchor portions 116 of the bristles transition into a liquid, at whichpoint the liquid of the anchor portions 116 of the bristles combinetogether into a single layer of liquid plastic that at least partiallycovers the lower surface 132 of the head plate 130. After the heat is nolonger applied, the melted anchor portions 116 of the bristlessolidify/harden to form the melt matte 106 or thin layer of plastic. Themelt mattes comprises a lower surface 107 that is opposite the lowersurface 132 of the head plate 130.

After the tooth cleaning elements 115 are secured to the head plate 130,the head plate 130 is secured to the head 110 such as by ultrasonicwelding or mechanical techniques (i.e., snap-fit, interference fit,slot-and-tab, or the like) so that the upper surface 133 of the headplate 130 forms at least a portion of the front surface 111 of the head110. When the head plate 130 is coupled to the head 110, the melt matte106 is located between the lower surface 132 of the head plate 130 andthe release component 150—as discussed further herein. The melt matte106, which is coupled directly to and in fact forms a part of the toothcleaning elements 115, prevents the tooth cleaning elements 115 frombeing pulled through the holes 131 in the head plate 130 to ensure thatthe tooth cleaning elements 115 remain attached to the head plate 130during use of the oral care implement 100.

As noted above, in another embodiment the tooth cleaning elements may beconnected to the head 110 using a technique known in the art as AMR. Inthis technique, the handle is formed integrally with the head plate as aone-piece structure. After the handle and the head plate are formed, thebristles are inserted into holes in the head plate so that thefree/cleaning ends of the bristles extend from the front surface of thehead plate and the bottom ends of the bristles are adjacent to the rearsurface of the head plate. After the bristles are inserted into theholes in the head plate, the bottom ends of the bristles are meltedtogether by applying heat thereto, thereby forming a melt matte at therear surface of the head plate. The melt matte is a thin layer ofplastic that is formed by melting the bottom ends of the bristles sothat the bottom ends of the bristles transition into a liquid, at whichpoint the liquid of the bottom ends of the bristles combine togetherinto a single layer of liquid plastic that at least partially covers therear surface of the head plate. After the heat is no longer applied, themelted bottom ends of the bristles solidify/harden to form the meltmatte/thin layer of plastic. In some embodiments, after formation of themelt matte, a tissue cleanser is injection molded onto the rear surfaceof the head plate, thereby trapping the melt matte between the tissuecleanser and the rear surface of the head plate. In other embodiments,other structures may be coupled to the rear surface of the head plate totrap the melt matte between the rear surface of the head plate and suchstructure without the structure necessarily being a tissue cleanser (thestructure can just be a plastic material that is used to form a smoothrear surface of the head, or the like).

Of course, techniques other than AFT and AMR can be used for mountingthe tooth cleaning elements 115 to the head 110, such as widely knownand used stapling techniques or the like. In such embodiments, the headplate 130 may be omitted and the tooth cleaning elements 115 may becoupled directly to the head 110. Furthermore, in a further modifiedversion of the AFT and AMR processes discussed above, the head plate 130may be formed by positioning the tooth cleaning elements 115 within amold, and then molding the head plate 130 around the tooth cleaningelements 115 via an injection molding process.

Referring again to FIGS. 1 and 2, in the exemplified embodiment theplurality of tooth cleaning elements 115 includes a plurality ofseparate tufts of bristles 114 and a plurality of elastomeric toothcleaning elements 103. Although illustrated herein as having a specificarrangement and shape, the arrangement of the tufts of bristles 114 andelastomeric tooth cleaning elements 103 as well as the shapes thereofcan be modified from that which is depicted in the figures. Thus, thecollective tooth cleaning elements 115 can be any pattern or arrangementand each one of the tooth cleaning elements 115 can have any desiredshape.

Referring now to FIG. 4, the head 110 may comprise one or more chambers160 that forms a cavity where the body 156 of the release component 150is positioned. The chamber 160 may comprise a floor 163 and a pluralityof sidewalls 162 that extend upward from the floor 163. The sidewalls162 may interest an upper surface 161.

Referring now to FIG. 7, in another embodiment, the release component150 comprises a body 156 formed from a polymeric matrix and a releasecomponent embedded therein. The body 156 includes a lower surface 152that is opposite an upper surface 151, whereby a side surface 152extends between the lower surface 152 and the upper surface 151. Thelower surface 152 of the body 156 of the release component 150 may be indirect contact with the lower surface 107 of the melt matte 106. Theupper surface 151 of the release component 150 may face opposite of thelower surface 107 of the melt matte 106.

The head 110 may comprise a chamber 160 that forms a cavity where thebody 156 of the release component 150 is positioned. The chamber 160 maycomprise an upper surface 161 that is opposite the lower surface 107 ofthe melt matte 106. The upper surface 161 may be circumscribed by aplurality of sidewalls 163. The head 110 may further comprise one ormore apertures 170 that extend from the rear surface 112 of the head 110to the upper surface 161 of the chamber 160. The apertures 170 allow forat least a portion of the release component 150 to reach the rearsurface 112 of the head 110 in the form of release islands 158 presenton the rear surface 112 of the head 110. The upper surface 161 and thesidewalls 163 of the chamber 160 may be formed by a main body 144 of thehead 110—as discussed further herein.

Referring to FIGS. 3-7 concurrently, the head 110 of the oral careimplement 100 will be described in more detail. As noted above, the head110 comprises the front surface 111, the rear surface 112 opposite thefront surface 111, and the peripheral surface 113 extending between thefront and rear surfaces 111, 112. The peripheral surface 113 forms aperiphery of the head 110 and defines the outermost boundary of the head110.

The head 110 of the oral care implement 100 comprises a main body 144that is formed of a hard-plastic material, such as any of the materialsnoted above for forming the handle 120 (including polypropylene and thelike). Furthermore, the head 110 comprises a release component 150 thatis coupled to the main body 144. The release component 150 may comprisea polymeric matrix and a release agent. The release agent may beuniformly distributed throughout the polymeric matrix of the releasecomponent 150.

As discussed in greater detailed herein, the polymeric matrix of thepresent invention is a water-dissolvable composition that allows for aslow-release of the release agent from the release component 150 overtime as the release component 150 is exposed to water (e.g., a user'ssaliva). The term “slow release” refers to a substantially continuousrelease of the release agent from the release component 150 over thecourse of at least three months based on exposure to water at least oncea day—preferably twice a day—for a time period suitable for toothbrushing.

The release agent may be selected from any suitable compositions basedon the desired effect over the slow release time period. For example,the release agent may be a colorant having a predetermined color (e.g.,red, yellow, blue, orange, etc.), a flavoring agent, anti-bacterial ormicrobial agent, whitening agents (e.g., hydrogen peroxide), and thelike. Non-limiting examples of release agent include zinc oxide,activated charcoal, L-arginin, and combinations thereof. In someembodiments, the release agent may be a blend of L-arginin and zincoxide.

In a non-limiting example, the release component 150 may be a colorant.As the polymeric matrix is exposed to water during continual usage ofthe oral care implement—e.g., routine tooth brushing—the colorant willbe depleted from the release component 150, which causes a correspondingcolor change in the release component 150. The change in color over timecan provide a visual indication of the amount of usage of the oral careimplement. With enough color change corresponding to the maximumrecommended usage of the oral care implement, a user can be informedwhen it is an appropriate time to replace the oral care implement. Insimilar embodiments, the release agent can be a flavoring agent—wherebythe release of the flavoring agent causes a corresponding loss of flavorlevels in the release component 150. The loss of flavor indicates anappropriate time to replace the oral care implement. Additionally, therelease agent can be a flavoring agent, whereby the release of theflavoring agent a change in flavor profile. The change in flavor profilecan provide a complementary sensorial or polarizing flavor experience tothe user.

In other embodiments, the oral care implement may comprise ananti-bacterial or anti-microbial agent (or a whitening agent) that doesnot provide a visual or taste indication of when to replace the oralcare implement. Rather, in these embodiments, the release agent may beprovided in an amount based on the release profile of the polymericmatrix, which is correlated to the typical lifespan of an oral careimplement. In a non-limiting example, the release agent may be activatedcharcoal—i.e., an anti-microbial agent. For an oral care implementhaving a predetermined lifespan based on regular usage and comprisingthe release component 150, the anti-microbial agent may be present inthe release component 150 in a pre-selected concentration that allowsfor continual release of the anti-microbial agent from the releasecomponent 150 over the entirety of that predetermined lifespan.Additionally, the concentration of the anti-microbial agent may bepre-selected such that once the predetermined lifespan of the oral careimplement is completed, the release component 150 may be substantiallydepleted of the anti-microbial agent.

Generally, the release agent may be present in an amount ranging fromabout 0.1 wt. % to about 15.0 wt. % based on the total weight of therelease component 150—including all amounts and sub-rangesthere-between. Based on the desired release agent (i.e., colorant vs.anti-microbial agent), the specific concentration of the release agentwithin the release component 150 may vary. In a non-limiting example,zinc oxide may be the release agent and present in a concentrationranging from about 0.5 wt. % to about 4.0 wt. %—preferably about 2.0 wt.% —based on the total weight of the release component 150, including allamounts and sub-ranges there-between. In a non-limiting example,activated charcoal may be the release agent and present in aconcentration ranging from about 0.1 wt. % to about 2.0 wt. %—preferablyabout 0.5 wt. % to about 1.0 wt. %—based on the total weight of therelease component 150, including all amounts and sub-rangesthere-between. In a non-limiting example, L-arginin may be the releaseagent and present in a concentration ranging from about 4 wt. % to about15 wt. %—preferably about 5.0 wt. % to about 10 wt. %—based on the totalweight of the release component 150, including all amounts andsub-ranges there-between.

The release component 150 may further comprise a non-releasable additivethat is dispersed within the polymeric matrix. The non-releasableadditive may be an organic or inorganic particle. In a preferredembodiment the non-releasable additive comprises an inorganic particlehaving either a uniform or varied particle size. In a non-limitingexample, the inorganic particle may provide a textured feel to therelease component 150.

The polymeric matrix of the present invention comprises a first polymer.The first polymer is a graft polymer. The graft polymer may compriseunits that are formed from at least one of the following compounds I,II, III, and/or IV:

Wherein Compound I is caprolactam, Compound II is vinyl acetate,Compound III is ethylene glycol, and Compound IV is ethylene. The term“graft polymer” is an art accepted term referring to segmentedcopolymers having a linear backbone of one composite and randomlydistributed branches of another composite. Therefore, the graft polymerthat is the first polymer may have branches formed from at least one ofthe Compounds I, II, III, and/or IV. In some embodiments, the firstpolymer may be polyvinyl caprolactam-polyvinylacetate-polyethyleneglycol graft polymer. The first polymer may be a resilient and flexibleelastomeric material, such as a thermoplastic elastomer. According tosome embodiments, the polymeric matrix may be formed from about 100 wt.% of the first polymer.

According to some embodiments, the polymeric matrix may comprise asecond polymer. The second polymer may be different from the firstpolymer. The second polymer may be polyvinylpyrrolidone. The first andsecond polymer may be present in the polymeric matrix in a weight ratioranging from about 7:1 to about 11:1—preferably about 8:1 to about10:1—including all ratios and subranges there-between. is a graftpolymer. In a preferred embodiment, the first and second polymer may bepresent in the polymeric matrix in a weight ratio of about 9:1.

According to some embodiments, the polymeric matrix may comprise a fattycomponent. The fatty component may be a fatty acid. The fatty acid mayhave the following formula I:

Wherein R may be a C14, C15, C16, C17, C18, C19, or C20 linear carbonchain. In a referred embodiment, R may be selected from a C16, C17, orC18 linear carbon chain. The R carbon chain may be saturated or containunsaturated C═C bonds. The first polymer and the fatty component may bepresent in the polymeric matrix in a weight ratio ranging from about 7:1to about 11:1—preferably about 8:1 to about 10:1—including all ratiosand subranges there-between. is a graft polymer. In a preferredembodiment, the first polymer and the fatty component may be present inthe polymeric matrix in a weight ratio of about 9:1.

The release component 150 of the present invention may be formed byinjection molding a blend of the release agent and the first polymer.The benefit of using the first polymer to form the polymeric matrix isthat the release component 150 may be formed at a processing temperatureranging from about 110° C. to about 200° C.—including all temperatureand sub-ranges there-between. Although not explicitly recited, thephrase “including all temperature and sub-ranges there-between” is meantto encompass all integer values that exist between the lower limittemperature of 110° C. and the upper limit temperature of 200° C. Forexample, the temperature range from about 110° C. to about 200°C.—including all temperature and sub-ranges there-between—includessub-ranges extending from about 130° C. to about 200° C. Additionally,the term “processing temperature” refers to a temperature at which aprecursor composition—i.e., a blend of the first polymer and releaseagent, optionally with the second polymer and/or fatty component—isinjection molded directly onto the head 110 of the oral care implement100 to form the release component 150, whereby the resulting polymermatrix does not degrade and does not burn.

In some embodiments, the processing temperature of the polymeric matrixis greater than or equal to 130° C. In particular, the processingtemperature may range from 130° C. to about 200° C.—including alltemperatures and sub-ranges there-between. In some embodiments, theprocessing temperature of the polymeric matrix is greater than or equalto 135° C. In particular, the processing temperature may range from 135°C. to about 200° C.—including all temperatures and sub-rangesthere-between. In some embodiments, the processing temperature of thepolymeric matrix is greater than or equal to 140° C. In particular, theprocessing temperature may range from 140° C. to about 200° C.—includingall temperatures and sub-ranges there-between. In some embodiments, theprocessing temperature of the polymeric matrix is greater than or equalto 145° C. In particular, the processing temperature may range from 145°C. to about 200° C.—including all temperatures and sub-rangesthere-between. In some embodiments, the processing temperature may begreater than or equal to about 150° C. These processing temperatures mayresult in the formation of the release component 150 on the head 110 ofthe oral care implement 100.

The first polymer—alone or in combination with the second polymer and/orthe fatty component—provides for a precursor composition that can befurther blended with the release agent and processed at hightemperatures in an injection molding process. The benefit is theformation of a water-dissolvable release component 150 that allows for aslow-release of the release agent from the release component 150 overtime when the release component 150 is exposed to water (e.g., a user'ssaliva). Previously, water-dissolvable compositions were not able to beprocessed at such high temperatures without substantial degradation ofthe material and/or loss of slow-release performance. However, it hasbeen discovered that by using the first polymer described herein, theresulting release component 150 can achieve both (1) the desired slowrelease water-dissolvable characteristics and (2) be processed at hightemperatures that are suitable for injection molding, therebyfacilitating production of the oral care implement but decreasingmanufacturing time.

According to the present invention, not only can the release component150 be formed using processing temperatures greater than or equal to110° C. (preferably, greater than or equal to 120° C., 130° C., 140° C.,and 150° C.) without degradation or the polymeric matrix, but it hasbeen surprisingly discovered that the polymeric matrix further preventscertain release components from decomposing and/or prematurely beingreleased during the manufacture of the release component 150.

The following a non-limiting example is provided to better explain thisphenomenon—the release component may be an additive that is a whiteningagent (e.g., hydrogen peroxide). Such additives may have a decompositiontemperature that is less than processing temperature. Stated otherwise,the release agent and the first polymer (and second polymer, if present)may be processed at a temperature that is greater than the decompositiontemperature of the release component. According to the presentinvention, the term “decomposition temperature” is a temperature atwhich a compound transforms from a first chemical composition into asecond chemical composition that is chemically distinct from the firstfrom the first chemical composition. For example, hydrogen peroxide maydecompose at a temperature of about 150° C. into water (H₂O) and Oxygen(O₂). Therefore, previously, it was undesirable to process such releasecomponents at temperatures above their decomposition temperature due tothe release components being modified into different chemically distinctcompounds that resulted in the loss of the desired additive benefit(e.g., tooth whitening). However, it has been surprisingly discoveredthat the first polymer provides an unexpected protective benefit to suchrelease components—even when the first polymer and the release componentare processed at temperatures above the decomposition temperature of therelease agent. Although the non-limiting example discussed herein isdirected to hydrogen peroxide—which has a decomposition temperature of150° C.—it should be understood that other release components may alsobenefit from the unexpected protective nature of the first polymer atother decomposition temperatures (i.e., the decomposition temperature ofthe release agent is not limited to 150° C.). Rather, the presentinvention is directed to the general relationship that releasecomponents may be processed at temperature exceeding their decompositiontemperature without the release component being modified into adifferent chemically distinct compound and/or compounds.

In another non-limiting example, the release component may be aflavoring agent having a volatile nature. Such volatile nature is due tothe high vapor pressure of such flavoring agents at relatively lowtemperatures (i.e., room temperature). When these flavoring agents areexposed to high processing temperatures (i.e., ≥110° C.), there is asubstantial risk of fuming or vapor formation, thereby resulting in apremature release such flavor agents from the polymeric matrix. In anon-limiting example, the flavoring agent may be menthol—which has avapor pressure of about 0.197 atm at 100° C. However, it has beensurprisingly discovered that using the first polymer—alone or incombination with the second polymer and/or the fattycomponent—surprisingly eliminates the release of fumes and/or vapor evenat high processing temperatures (i.e., ≥110° C.), thereby eliminatingpremature loss of volatile flavoring agents from the polymeric matrixduring formation of the release component 150 at high processingtemperatures. Therefore, the present invention further includes that therelease component 150 may further comprise flavoring agents that exhibita vapor pressure of at least 0.18 atm at 100° C.—preferably at leastabout 0.19 atm at about 100° C., even more preferably about 0.2 atm atabout 100° C.—without substantial risk of fuming or vapor formation,thereby preventing the premature release such flavor agents from thepolymeric matrix.

Referring now to FIG. 7, the release component 150 may be formed byinjection molding a blend of the first polymer and release component (aswell as the second polymer and/or the fatty component) into the cavityformed by the chamber 160. Specifically, before the melt-matte 106 andhead plate 130 are attached to the head 110, the blend of the firstpolymer and release component (as well as the second polymer and/or thefatty component) are injection molded into the chamber 160 via theopening on the front surface 111 of the head 110. The release component150 contacts the sidewalls 163 and upper surface 161 of the chamber 160,and at least a portion of the release component 150 passes through theapertures 170 to be exposed on the rear surface 112 of the head. Oncecooled, the portion of the body 156 that remains within the chamber 160and contacts the upper surface 161 acts as an anchor thereby holding therelease islands 158 in place on the rear surface 112 of the head 110.Additionally, once the release component 150 is inserted into thechamber 160, the release component 150 may be in direct contact with atleast one of the sidewall 163 and/or the upper surface 161 that isformed of polypropylene.

The release islands 158 may extend through the apertures 170 and beyondthe main body 144 in a direction extending from the front surface 111 tothe rear surface 112 of the head 110 such that a top portion of therelease island 158 is taller than the main body 144 on the rear surface112 of the head 110.

Additionally, the size of the apertures 170 may be modified to controlthe exposed surface area of the release component 150 on the rearsurface 112 of the head 110. By controlling the exposed surface area ofthe release component 150 via controlling the size of the releaseislands 158, the amount of the release agent that can be released fromthe release component 150 within a given period can also be modified.For example, when the apertures 170 increase in size, the amount ofrelease agent that can be delivered to a user's mouth may also beincreased without changing the innate release characteristics of thefirst polymer. Conversely, when the apertures 170 decrease in size, theamount of release agent that can be delivered to a user's mouth may alsobe decrease without modifying the innate release characteristics of thefirst polymer.

According to such embodiments, the release component 150 may create avaried texture on the rear surface 112 of the head 110. In otherembodiments, the top portion 151 of the release component 150 may besubstantially flush with the rear surface 112 of the head 110.

Although not pictured, the oral care implement may further compriseelastomeric soft tissue cleansers that serve to clean the user's tongueand soft tissue surfaces and to protect the user's gums. The soft tissuecleansers may comprise protuberances that extend outward from the head110. The elastomeric soft tissue cleanser may be positioned on theperipheral surface 113 of the head 110 and thus reduces the impact ofthe hard plastic of the base 144 against the user's gums during use ofthe toothbrush. The elastomeric soft tissue cleanser may also includeraised features that protrude beyond the rear surface 112 of the head110 and can also be used for cleaning/scraping a user's tongue. Theelastomeric soft tissue cleanser may also be positioned on the rearsurface 112 of the head 110 and surround the release component 150—i.e.,not cover the release component 150. On the rear surface 112 of the head110, the elastomeric soft tissue cleanser can be used to clean and scruba user's tongue and other soft tissue surfaces. The elastomeric softtissue cleanser on the rear surface 112 and/or the peripheral surface113 results in a highly desirable aesthetic appearance for the oral careimplement 100.

The protuberances present on the elastomeric soft tissue cleanser may bein the form of a nub. As used herein a “nub” generally refers to acolumn-like protrusion (without limitation to the cross-sectional shapeof the protrusion) which is upstanding from a base surface. In a generalsense, the protuberances in the preferred construction have a heightthat is greater than the width at the base of the protuberance (asmeasured in the longest direction). Nevertheless, protuberances or nubscould include projections wherein the widths and heights are roughly thesame or wherein the heights are somewhat smaller than the base widths.Moreover, in some circumstances (e.g., where the protuberances taper toa tip or include a base portion that narrows to a smaller projection),the base width can be substantially larger than the height. Furthermore,in the exemplified embodiment the plurality of protuberances may havevarying heights such that some of the protuberances are taller thanother of the protuberances. The elastomeric soft tissue cleanser may bea flexible material, such as a thermoplastic elastomer.

While the invention has been described with respect to specific examplesincluding presently preferred modes of carrying out the invention, thoseskilled in the art will appreciate that there are numerous variationsand permutations of the above described systems and techniques. It is tobe understood that other embodiments may be utilized and structural andfunctional modifications may be made without departing from the scope ofthe present invention. Thus, the spirit and scope of the inventionshould be construed broadly as set forth in the appended claims.

What is claimed is:
 1. A method of forming an oral care implementcomprising: injection molding a composition comprising a graft polymeronto a head of an oral care implement at a temperature equal to orgreater than 130° C. to form a water-dissolvable polymer matrix.
 2. Themethod according to claim 1, wherein the graft polymer comprises unitsformed from caprolactam, vinyl acetate, and ethylene glycol.
 3. Themethod according to claim 1, wherein the composition comprises a blendof the graft polymer and a fatty acid.
 4. The method according to claim3, wherein the fatty acid includes a C16 to C18 carbon chain.
 5. Themethod according to claim 1, wherein the composition comprises a blendof the graft polymer and polyvinylpyrrolidone.
 6. The method accordingto claim 1, wherein the head comprises a surface formed frompolypropylene and the composition is injection molded to the surface ofthe head.
 7. The method according to claim 1, wherein the compositionfurther comprises a release agent selected from the group of zinc oxide,activated charcoal, L-arginin, flavor agents, and colorants.
 8. A methodof forming an oral care implement comprising: injection molding acomposition onto a head of the oral care implement, the compositioncomprising a graft polymer that comprises units formed from caprolactam,vinyl acetate, and ethylene glycol to form a water-dissolvable polymermatrix.
 9. The method according to claim 8, wherein the compositioncomprises a blend of the graft polymer and a fatty acid.
 10. The methodaccording to claim 9, wherein the fatty acid includes a C16 to C18carbon chain.
 11. The method according to claim 8, wherein thecomposition comprises a blend of the graft polymer andpolyvinylpyrrolidone.
 12. The method according to claim 8, wherein thehead comprises a surface formed from polypropylene and the compositionis injection molded to the surface of the head.
 13. The method accordingto claim 8, wherein the composition further comprises a release agentselected from the group of zinc oxide, activated charcoal, L-arginin,flavor agents, and colorants.
 14. A method of forming an oral careimplement comprising: injection molding a composition comprising a blendof a graft polymer and an additive onto a head of an oral care implementat a temperature equal to or greater than 130° C. to form awater-dissolvable polymer matrix; wherein the additive has adecomposition temperature less than or equal to 150° C.
 15. The methodaccording to claim 14, wherein the temperature at which the compositionis injection molded to the head of the oral care implement is equal toor greater than 150° C.
 16. The method according to claim 14, whereinthe additive is hydrogen peroxide or a flavoring agent.
 17. The methodaccording to claim 14, wherein the graft polymer comprises units formedfrom caprolactam, vinyl acetate, and ethylene glycol.
 18. The methodaccording to claim 14, wherein the composition forms a water-dissolvablepolymer matrix that releases the additive when exposed to water.
 19. Themethod according to claim 14, wherein the additive has a vapor pressureof at least about 0.18 atm at 100° C.